Lamp element and method of making same



Sept. 2, 1941. Y c H FULP 2,254,362

LAMP ELEMENT AND METHOD OF MAKING SAME Filed 'Dec. 21, 1959 2 Sheets-Sheet l Chester H Fu/p Sept. 2, 1941. c; FULP 2,254362 LAMP ELEMENT AND METHOD OF MAKING SAME Filed Dec. ,21, 19:59 2 Sheets-Sheet 2 mm imi uwfxwmj nunnun Patented 2, 1941 PATENT. OFFICE sgzsusz mm mm m 'us'rnon or-rumm Application December 21, 1939, Serial No. 310,319

' 13 Claims. (01. 176-4.)

This invention relates to improvements in a lamp element and a method of making the same,

the element including a filament of the character ofa resistance coil which, while highly duirable for use in connection with incandescent lamp filaments, may also be desirable with other electrical devices, as will be apparent to onetilled in the art.

In many cases, such, for example, as traffic signal lights, it is highly desirable to use a multiment burns out, the particular lampis not totally darkened but will operate with a goodly portion of its illuminating efficiency on the remaining filament or filaments. I am aware that in the past many and various designs for incandescent lamps having two or more filaments have been developed, but in no instance of which I am aware have these formerly known devices been capable of sufilciently economical manufacturer to warrant a'wide commercial usage.

With the foregoing in mind, it is an important object of the present invention to provide a multi-filament lamp element which may be manufactured at only anegligible increase in cost over the cost of manufacture of a single filament incandescent lamp.

A further object of the invention is the provision of a lamp element embodying more than two filaments, in which the filaments may be assembled with the'lead-in wires by very simple attaching operations and without the necessity of any especially designed machines to accommodate the novel construction Another object of the invention is the provision of a triple-filament lamp element in which the triple-filament may be attached to the lead-in wires by four simple clamping op- A further object of the invention is the provision of a resistance element having at least .three resistance 'segmentss'o arranged as to provide the efi'ect of a completely closed magnetic field between any two of the segments.

inthe provision of'a adapted for use as a multi-filament for an incandescent lamp so arranged that the magnetic field set up by each filament is in a direction'from the same lead-in wire to the other.

Still a further object of the invention is the provision of a new and novel method of making a multi-filamentlamp element. 7

While some of the more salient features, char- 10 acteristics and advantages of the present invenfilarnlent incandescentlamp sothat ifone filation have been above pointed'qut, others will become apparent from the following disclosures,

taken in conilmction with the accompanying drawingsin which:

is Figure-.1 is a side-elevationalview of is mcandescent lamp containing a lamp element emfeatures of the present invention and constructed in accordance with the novel meth- .odformingapartofthisinvention; Figure 2- is an enlarged. fragmentary, perspective view of the lead-in wires included in the lamp element of Figure 1;

Figure 3 is an enlarged, exploded view of a triple-filament lamp, indicating one method of construction of such a triple-filament;

l 'igureflsagreatlyenlargedviewofthepreferred1 form of filament for the lamp of Figure Figure 5 illustrates the lamp filament before I S0 attachment to the lead-in wires:

as Figure 8 indicates .the next advanced step in v the practice of my novel method; and

Figure 9 illustrates the fin'al step in themaking of the lamp element. As shown on the drawings:

so It will be appreciated that m the drawings the filament coil and lead-in wires. are greatly exaggerated for the purpose of clarity, to better illustrate the winding of the filament coil and the clamping formation provided on the inner ends of the lead-in wires. This exaggeration is especially true in connection with the showing v of the inner end formations onthe lead-in wires, and it will be readily understood that the clamping portions of these wires need not be of as large a proportional size as illustrated.

In the illustrated embodiment of this invention, there 'is shown an incandescent lamp including the usual base it, the transparent en-. velope or bulb II, with the stem II carrying the Still another feature of the invention resides t5 button rod i8 terminating in the button withinthestem ifinaknownmannerandextending upwardly on either side of the button rod aretbe lead-in wires l l and i8 respectively. These lead-in wires make contact with the customary-contact points on the base in a wellknown manner. Carried on the inner ends of thelead-inwires lland II andalsoaidedby any supportsflf desired, associated with the button M is my novel multi-filament element l1. Herein and in the appended claims, where the term "lamp elemen is used, such term is to be construed as referring .to my novel arrangement and connection of lead-in wires and filaments.

In the modern manufacture of incandescent lamps, it is customary to provide a bent portion in the end of a lead-in wire, so that it may be clamped to the filament and thus support the filament and establish electrical connection between the filament and lead-in wire. In the present invention, eachlead-in wire is preferably provided with a plurality of clamping portions. In the illustrated instance, with reference more particularly to Figure 2, it will be seen that the lead-in win It is provided with a lateral reverse bend II and also a vertical reverse bend l9, each forming a clamping portion. The legs of each of theclamping portions l8 and is may be squeezed together over a part of the filament wire to Join the filament to the lead-in wire. The other lead-in wire it is provided with a similar outwardly'and laterally extending clamping portion 20 and a vertically extending clamping portion 2|. For convenience in assembly, it is preferable to have the free leg of the vertical portion l9 extending in the opposite direction to the free leg on the vertical portion 2i, as exemplified in the showing in Figure 2. The bent clamping formations on each lead-in wire may be readily provided with a Jig arrangement in an economical manner.

While a two-filament lamp is highly desirable, a three-filament provides much greater efficiency upon the, burning out of a single filament. With the present invention, the cost of providing a three-filament arrangement is not only a neglithan most two-filament arrangements known heretofore.

One way of providing a three-filament arrangement is illustrated in Figure 3, wherein three separate filament coils 22, 23 and 24, respectively, are shown. The filament coils 22 and 2 are preferably substantially semi-circular, and the coil 23 extends across the loop formed by the coils 22 and 24 when they are Joined together. With this arrangement, it is preferable to weld or similarly unite the adjacent terminii of all three filaments on each side of the loop formed by the coils 22 and 24. The joined terminii may then be clamped or otherwise attached to a leadin wire. The center or cross-filament 23 may be either substantially S-shaped, as shown, or may bow upwardly or downwardly. The deviation from a straight line of this particular filament is only due to simplicity in manufacture by windlog all of the filament coilswith the same number of turns. It is preferable to have all the filament coilsof the same resistance value so, if desired,

2,254,362 ll, all within the base and envelope. Supported the central filament 23 could be of different material, or the turns could be made more numerous so that this filament would extend straight across the loop formed by the coils 22 and 24. This procedure of providing a threefilament arrangement-is objectionably expensive in the manufacture of lamps for most commercial purposes.

In Figures 4 and 5, I have illustrated my preferred form of a three-filament arrangement, which is generally indicated by numeral IT. The structure I! might be better termed an integral segmented filament. It preferably consists of a single integral coil having a terminus 25 at one end, a coil segment 26, an uncoiled portion or joint 21, a second coll segment 28, another Joint 29, a third coil segment 20, and a final terminus 3|. For purposes of economy, the segments 2|, 2! and iii are preferably of equal size and have the same. number of turns so that all are of the same resistance value. The joints 21 and 28 are readily provided during the winding of the filament coil by simply skipping a turn at these particular points. In the resultant lamp assemment arrangement to the lead-in wires, as illustrated in Figures 6 to 9, inclusive.

All of the steps illustrated in these figures may be carried out on lamp manufacturing machines now in existence and do not require the development of special new machinery for the purpose of assembling the lamp element.

The first step in the assembly is shown in Figure 6, and there it will be seen that the terminus 2! is clamped in the formation I I by compress-. ing the legs of this formation together upon the terminus. The filament coil 28 is next formed substantially in the nature of a half-circle, the filament being longer than the distance between the lead-in wires, and the joint 21 is clamped in the formation 20 on the other wire it, as seen in Figure 7. The following step consists in bending the filament coil 28 substantially in the form of a half-circle opposite the coil 26 to substantially complete the loop, and clamp the joint II in the formation It on the wire II.' The final step consists in disposing the filament coil ll in the illustrated 8-shape, or otherwise, across the loop formed by the coils 28 and 28, and clamping the final terminus 3| in the formation 2| on the wire l6. It is therefore apparent that with four simple clamping operations, a three-filament arrangement is provided, and in the assembly operation only two more simple clamping operations are necessary over the two operations necessary for the attachment of a single filament.

With reference to Figure 4, which shows a greatly exaggerated view of the triple-filament arrangement in final position, it will be seen that with all the coil segments 26, and 30 having turns in the same direction, the magnetic fields set up by these coils all will pass along the respective coil from left to right as seen in this figure, assuming that the current enters through the lead-in wire it and departs through the leadeinwire n. The terminus! is co will be from the joint is to the joint 21. Finally,

the magnetic field in the middle filament II will be from the Joint I! to the terminus 3| or the lead-in wire is. It will be noted that these m netic fields approximately buck each other. Bearing in mind the tact that the showings of the clamping arrangements on the lead-in wires ii and I! ar greatly exaggerated, it will be seen that substantially closed loops are provided between any pair or filament coils. In the event two filament coils burn out, the lamp will not fail, but some illumination will still be provided by the remaining coil. Consequently, it the lamp is used in trafilc signals or the like, there is ample time for replacementbeiore ultimate iailure oi the lamp and still have the signal operating properly until replacement is finally made.

It will be appreciated that the particular filament arrangement may be utilized in connection with other and various devices and incandescent lamps, such as resistance coils, heating coils, etc.

,It will further be noted that with this arrangement many undesirable efiects in the circuit are eliminated, and the element is substantially unresponsive to outside disturbances so that it may be desirable for use in the form of miniature or larger elements in radio and television work.

It will further be appreciated that the filament or resistance element may be made of any desirable material, such, for example, as tungsten or a tungsten alloy when it is used in connection with incandescent lamps.

From the foregoing, it is apparent that I have provided a novel filament or resistance arrangement and a novel lamp element wherein a multifilament arrangement is provided at only a negligible increase in cost over a single-filament arrangement. It will also be appreciated that I have provided a new and novel method for making a lamp element which is extremely economical to practice and results in a very highly efiicient element. 7

It will, oi course, be understood that numerous details of construction may be varied through a wide range without departing from the principles oi this'invention, and it is therefore not the purpose to limit the patent-granted hereon otherwise than is necessitated by the scope oi the appended claims.

I claim as my invention:

1. man incandescentlamp element. a pair of spaced lead-in'wires each having an integral end portion shaped to provide a pair or. bendable clamping parts, and an integral triple segmented filament with each endand each p int between adjacent segments thereof clamped in a difierent, I one or said parts. 2. The methodo! making a resistance element, including the steps of winding a coil, shipping a turn attwomacedpcints todefine three connected coil segments. and shaping the winding substantially into alcopwith twossgments iorming the loop and across the loop.

3. The method or making a relistance 'element, including the st ps or windings. coil, skipping a turn at two spaced points to;de'fine three connected'coil segments, and shaping'the'winding substantially into a loop with two segments assess: v v 3 iormingtheioopand the thirdsegment extending across the loo electrically connecting each free end of the winding to the adjacent portion where a turn was shipped, and connecting a conductor to each connection between a tree coil end and the portion where a turn was skipped.

4. The method of making a resistance element, including the steps winding a coil. skipping a turn at a predetermined point to define 10 two coil segments, and attaching a third coil segment to the connected two segments in a manner to provide a substantially closed loop oi'two segnnents with another segment extending thereacross.

1g 5. The method of making a lamp element, in-

cluding the steps of winding an integral filament -coil with all turns in the same direction, shipping a turn at spaced intervals to provide equal coil segments, providing a pair or lead-in wires, and

attaching one free end oi the filament coil to one lead-in wire, attaching the next portion between segments to the other wire, attaching the next portion between segments to the first wire.

and proceeding thus until the other free end is attached toone of the wires.

. s. The method or making a lamp element, in-

cluding the steps of bending the ends or a pair oi lead-in wires to provide a pair of adjacent and integral clamping portions on .each wire, 'i'orming an integral triple segmented filament, clamping a free end or the filament in one 01 said portions on one wire, the next space between segments in a portion on the other wire, the next such space inthe otherportionoithefirstwiraandthe 5 final free end to the other portion of the other '1. The method of making a multi-filament.

lamp element, including the steps of forming a segmented filament, bending the end oi each or 40 a pair or lead-in wires to provide a plurality of clamping portions in difi'erent planes, and clamping an endor the filament to one wire, the next space between segments to the other wire, and

alternating thus between the wires until the final 65 end of the filament is clamped.

8. The method of making a multi-filament lamp element, including the steps of bending an end of a lead-in wire to provide a laterally extendingslnpingportlonandaverticallyextending clamping portion, providing another similarly shaped lead-in wire spaced from the first 66 termediate points each clamped in a difierent one or said parts.

11. In an incandescent lamp element, a' pair of spaced lead-in wires each having a lateral U-bend-and a vertical U-bend toprovide a pair. 7 of compressible clamping parts, the lateral bends extending in opposite directions and the verticaibendshavingtheirrreesides pp sitelydisposed and-an elongated filament disposed with its ends and certain immediate points each clampedinadiiierentoneorsaidparts.

lnmp element, including the step; of bending the ends of a pair of lead-in wires to provide a plunlity of adjacent clamping portion: on each wire, end clamping an end oi o filament in a. portion of one wire, an intermediate point in a. portion 0! the other wire, and elternatin: thus between the wires until the final end 0! the filament is clamped.

12. The method or making a. multi-filement CHESTER H. PULP. 

